Driving method of a plasma display panel of alternating current for creation of gray level gradations

ABSTRACT

The present invention provides a gray level display AC-type PDP driving method comprising (a) dividing a single image frame into n number of subframes, each of the subframes having predetermined number of sustaining pulses; (b) selecting scan electrodes whose number is identical to the number of said subframes, assigning specific subframes to said selected scan electrodes, sequentially providing scanning pulses having different phases on said selected scan electrodes and applying addressing pulses on said data electrodes in order to designate pixels to be displayed, and alternately supplying the predetermined number of sustaining pulses onto the selected scan electrodes and said data electrodes, to thereby display said assigned subframes for said selected display lines; (c) shifting by one or more than scan electrode(s) from each of said selected scan electrodes; and (d) repeating said shifting of step (c) and displaying of said assigned subframes until each of said divided subframes is displayed for all the display lines, to thereby display a image frame. According to the present invention, it is possible to eliminate a suspending time and to provide advantages of advanced driving stability, high luminance and improved contrast.

FIELD OF THE INVENTION

The present invention relates to a plasma technique; and, moreparticularly, to a method and an apparatus, for use in a display systemsuch as a TV plasma video module employing an AC-type plasma displaypanel, for driving an AC-type plasma display panel capable of displayinga gray level.

DESCRIPTION OF THE PRIOR ART

A plasma display panel (referred to as “PDP” hereinafter) is a devicewhich displays letters or pictures by using light emitted from plasmagenerated during gaseous discharge. The PDP is classified into a DC-typeand an AC-type depending on a driving method for providing electricfield thereto in order to make the plasma.

Since the PDP has advantageous characteristics such as large screen sizemore than 40 inches, ability to display full-color images and wideviewing angle compared with other flat panel devices, it results in arapid increase in its application area such a next generation HDTVcapable of hanging on the wall and a multimedia display apparatuscombining a TV and a personal computer.

There are several methods for driving the AC-type PDP. One of themethods is disclosed in U.S. Pat. No. 5,541,618, assigned to FujitsuLimited. An address display period separated (ADS) sub-field methoddisclosed in same will be illustrated hereinafter.

In accordance with the above patent, one image frame is divided into nnumber of subframes. Each of the subframes includes: an addressingperiod subsequently providing scan pulses to all scan electrodes inorder to indicate cells to be lit; and a display period having apredetermined sustain pulses and concurrently applying sustain pulses toall the scan electrodes, wherein a number of the sustain pulses ispredetermined differently for each subframe.

As shown above, the scan pulses are continuously provided onto all thescan electrodes and address pulses are applied onto data electrodes inresponse to picture data to be displayed. However, according to the ADSsub-field method, since every subframe should have an addressing periodfor addressing all the scan lines, the display period is relativelyshortened. Therefore, the brightness of an image may be decreased.

For example, in order to prevent users from feeling flickers on thescreen, the time for controlling illumination of one frame should belimited about {fraction (1/60)} sec or less, namely 16.67 ms. In NTSCsystem having 480 scan lines, if one image frame is divided into 8number of subframes, it takes about 11 to 12 ms in addressing one imageframe. Because the remaining time for the display period which TV viewercan substantially recognize the image is only 5 to 6 ms, the efficiencybecomes only 30% and the brightness of the image is reduced. However, ifincreasing frequency of sustain pulse in order to compensate thebrightness reduction, power consumption is increased and reliability ofdriving is also decreased.

In particular, in case of HDTV having 1024 scan lines, because it takesabout 24 to 25 ms in addressing one image frame, there is no theremaining time for the display period. As a result, the TV viewer cannotrecognize the image. Also, since pixels corresponding to scan electrodesare continuously selected for an addressing period, the reliability ofdriving is reduced by a result of static delay effect which occurs indischarge firing.

There have been proposed another AC-type PDP driving method forproviding a gradation of the display brightness, such as the article byNakamura A. O. “Drive for 40-in.-Diagonal Full-Color as Plasma Display”SID 95 DIGEST pp. 807-810. According to the above method, one imageframe is divided with time into n number of subframes which of each havea predetermined number of sustain pulses, each subframe includes asingle display period for applying a predetermined number of sustainpulses to all the scan electrodes and an addressing period in whichprimary discharges is simultaneously created in pixels corresponding toscanning electrode group, thereafter scanning pulses are sequentiallyformed on all scanning electrodes of this group, similarly, formation ofprimary discharge and scanning pulse are accomplished for other groupsof scanning electrodes.

Problem in the above method disclosed in “SID 95 DIGEST” is in thatsince each subframe should has a addressing period for all scanelectrodes, a display period for sustaining an image frame is inevitablyreduced, consequently brightness of an image is reduced. In this case,increasing frequency of sustain pulse in order to partially compensatethe brightness reduction may causes increase of power consumption andreduction of driving reliability.

Another method for displaying a picture half-brightness (gray scale) isdisclosed in U.S. Pat. No. 3,906,290 by Koichiro K. et al. A halftonepicture display can be achieved according to two methods, the firstbeing that the mean brightness of the picture element or luminescent dotbe made proportional to the turn-on period. The second method is thatthe mean brightness of the picture element or luminescent dot for theturn-on period be made proportional to the frequency of the sustainingvoltage.

Several embodiments are disclosed which incorporate one or both of theforegoing principles to achieve a halftone display.

However, in the above method, there is the fact that the image sharpnessand the brightness are reduced. To achieve an image of good quality, thenumber of subelement in a pixel should be larger, their brightnessshould be differently set.

Furthermore, according to the above method by Koichiro K. et al., oneimage frame is divided into n number of subframes, each subframe havinga predetermined number of the sustain pulses. Here, scan pulses areprovided onto scan electrodes and address pulses are applied onto dataelectrodes in response to picture data to be displayed.

To realize above method in an AC-type PDP driving circuit, it isnecessary to have a plurality of multi-discharge shift registers onlogic inputs of scanning pulse drive with complicated logic circuit ofconnection of their outputs, and it reduces reliability of driving andalso rises cost of the device.

Also, there is another driving method of the AC-type PDP for displayinggrey level gradation which is disclosed in EP patent No. 0,488,326A2 anddeveloped by NEC Corporation in Japan. According to the driving methodof NEC, one field is divided into n number of subfields, all of thesecond to last subfields have equal period T's, and the first subfieldhas period 2T's. All subfields also have different light emissionperiods, namely T′, T′/2, T′/4, T′/8, . . . , respectively.

According to this method, although the brightness of an image becomesabout 78.8%, since the light emission periods of some subframes haverelatively small periods and all pixels corresponding to given scanningelectrode are in “off” states, the efficiency of an image frame used fordisplaying cannot be increased more than 78.8%.

SUMMARY OF THE INVENTION

It is, therefore, a object of the present invention to provide a graylevel display AC-type PDP driving method capable of achieving highsharpness of an image, high brightness and improved reliability byeliminating the before-mentioned problems.

In accordance with one aspect of the present invention, a method fordriving an AC-type plasma display panel comprising two substratesseparated from each other, display electrodes and scan electrodesdisposed on one of said two substrates in parallel, a plurality ofdisplay lines consisting of one scan electrode and one or more displayelectrodes, a dielectric layer covering the display and the scanelectrodes, data electrodes disposed on the other of said twosubstrates, substantially orthogonal to said display lines, a number ofpixels formed on crossing points of a display line and a data electrode,spacers formed on one or both of said substrates to partition saidpixels, and gas filled in a space between the two substrates, saidmethod comprising the steps of: (a) dividing a single image frame into nnumber of subframes, each of the subframes having predetermined numberof sustaining pulses; (b) selecting display lines whose number isidentical to the number of said divided subframes, assigning specificsubframes to said selected display lines, sequentially providingscanning pulses having different phases on the scan electrodes of saidselected display lines and at the same time applying addressing pulseson is said data electrodes in order to designate pixels to be displayed,and alternately supplying the predetermined number of sustaining pulsesonto the selected scan electrodes and said commonly connected displayelectrodes, to thereby display said assigned subframes for each of saidselected display lines; (c) shifting by one or more than display linesfrom each of said selected display lines, and (d) repeating saidshifting of step (c) and displaying of said assigned subframes forselected display lines of step (b) until each of said divided subframesis displayed for all the display lines, to thereby display a imageframe.

In accordance with another aspect of the present invention, there isprovided a method for driving an AC-type plasma display panel capable ofdisplaying gray levels of an image frame which is divided into n numberof subframes, each subframe having predetermined sustain periods,wherein, for each subframe, scan pulses are provided onto selected scanelectrodes and addressing pulses are supplied onto data electrodes inresponse to display information, comprising: the number of sustainpulses, included in two adjacent subframes among the subframes,determined as:

R≧2S/(n+2)

wherein R is the number of sustain pulses; S represents the total numberof sustain pulses within the image frame; and n depicts the number ofthe subframes, the number of sustain pulses in a subframe being of anodd number.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the presentinvention will become apparent from the following detailed descriptionof preferred embodiments of the invention with reference to theaccompanying drawings, in which:

FIG. 1 represents a structure of a 4 electrode surface discharge AC-typePDP driving apparatus in accordance with the present invention;

FIG. 2 shows a schematic block diagram of a control micro circuit, foruse in the scan electrode driver in FIG. 1, for generating scan pulses;

FIG. 3 is a timing diagram of an image frame division in accordance witha driving method of the present invention;

FIG. 4 depicts a timing diagram of voltage pulses on electrodes of thePDP in accordance with the present invention;

FIG. 5a illustrates an electrode array of an AC-type PDP of a 3electrode surface discharge type;

FIG. 5b represents a cross-sectional view of cutting the electrode arrayof the AC-type PDP in FIG. 5a along lines I—I;

FIG. 6a describes an electrode array of an AC-type PDP of a 2 electrodeopposed-discharge type;

FIG. 6b shows a cross-sectional view of cutting the electrode array ofthe AC-type PDP in FIG. 6a along lines II—II;

FIG. 7 is a schematic block diagram of an AC-type PDP driving apparatusin accordance with the present invention;

FIG. 8a represents a timing diagram of a selective erasing mode inaccordance with the driving method of the present invention;

FIG. 8b depicts a timing diagram of a selective writing mode inaccordance with the driving method of the present invention;

FIG. 8c shows a timing diagram representing continuous sustain pulses inaccordance with the driving method of the present invention; and

FIGS. 9a and 9 b are timing diagrams in accordance with anotherembodiment of the present invention, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention will be illustrated in detailwith reference to the accompanying drawings.

Referring to FIG. 1, there is represented a structure of a gray leveldisplay AC-type PDP driving apparatus in accordance with the presentinvention. In FIG. 1, each pixel 5 comprises a first display electrode 6and a second display electrode 7 which are disposed in parallel witheach other; a scan electrode 8 located close to the second displayelectrode 7; a data electrode 9 crossing perpendicular to the first andthe second display electrodes 6 and 7 and the scan electrode 8. Thefirst and the second display electrodes 6 and 7 and the scan electrode 8are formed under an upper glass plate 10 and covered by a dielectriclayer 11. The data electrode 9 is disposed between spacers 13 on a lowerglass plate 12, orthogonal to the first and the second displayelectrodes 6 and 7 disposed on the upper glass plate 10, and covered bythree fluorescent layers 14 each emitting red(R), green(G) and blue(B)lights. The spacers 13 can be formed in the form of a stripe or a matrixand a pixel is formed on a crossing point between the display electrodesand the data electrode. Space between the upper glass plate 10 and thelower glass plate 12 is filled with a mixed gas of, e.g, Ne, He and Xe,and thereafter sealed. In this panel, one display line consists of afirst and a second display electrodes and a scan electrode, and a pitchof a pixel is set such as e.g., 1.05 mm.

The data electrodes 9 are connected to a data driver 15, which providespositive addressing pulses to the data electrodes 9 in response toinformation to be displayed within a given sustain period. The scanelectrodes 8 are connected to a scan electrode driver 16, which providesscan pulses to all of scan electrodes 8 selected in the given sustainperiod. All of the first and the second display electrodes 6 and 7 areunited into two groups and connected to a sustain pulse generator 17,which provides sustain pulses for each subframe.

FIG. 7 is a schematic block diagram of an AC-type PDP driving apparatus.This apparatus comprises a scan driver 16 for sequentially providingscan pulses onto the scan electrodes; upper and lower X-electrode driver15-1,15-2 for providing addressing pulses in response to display data; asustain driver 17-1,17-1 for supplying sustain pulses onto the displayelectrodes; and a controller 18 for controlling pulse timing of alldrivers.

Referring to FIG. 2, there is shown a schematic block diagram of acontrol micro circuit for use in the scan driver in FIG. 1 or 7 forgenerating scan pulses. The outputs of control micro-circuits correspondto output terminals Y1, Y2 and Y3 . . . of the scan driver 16. Thecontrol micro-circuit shown in FIG. 2 can be used such as e.g μ PD16305developed by NEC Corporation which comprises a 40 stage shift register 1having a CLK input and D data input for entry of input information whichthe latter being shifted later by a clock pulse. Information output fromthe shift register 1 is written on a register-latch 2 by means of apulse input from STB input. Information output from the register-latch 2is provided to a first input terminal of each of coincidence circuits 3,which have respective second input terminal, i.e. a BLK input terminalfor providing a blank pulse. Information output from the register-latch2 and blank pulse from a BLK input terminal is coupled by coincidencecircuit 3, the coupled information is provided to respective outputdrivers 4 for forming scan pulses at the output terminals Q1 to Q40.

The driving principle according to the present invention will beillustrated hereafter by the above mentioned devices. The AC-PDP drivingmethod for displaying gray level gradation comprises: dividing an imageframe into n number of subframes; and setting the predetermined numberof sustaining period for each subframe wherein scan pulses are appliedon scan electrodes to be selected and address pulses are applied on dataelectrodes in accordance with information to be displayed. Also, thetotal number of sustaining periods(R) for any two adjacent subframes ofcontinuous subframes is set by the empiric ratio as follows:

R≧2S/(n+2)

where S is total number of sustaining periods in an image frame, thenumber of sustaining periods in any subframe is odd.

The scan pulses are generated on the scan electrodes by the controlmicro-circuits having “γ” outputs, respectively. In a given sustainingperiod, scanning pulses is formed only on any one of outputs of thecontrol micro-circuits. The “γ” value is determined by the conditionγ≦R/2. The scan electrodes only of the same name(even or odd) areseparately connected to one control micro-circuit.

Setting the total number of sustaining periods(R) for any two adjacentsubframes of continuous subframes by the ratio R≧2S/(n+2) and odd numberof sustaining periods in any subframe make it possible to select numbersof the scan electrodes which are distinguished even number with oddnumber at least by R, to use control micro-circuits with a large numberof outputs “γ” and to provide improved driving reliability.

Formation scanning pulses only on one of the control micro-circuitoutputs in given sustaining periods makes it possible to carry outselection of all scan electrodes without change of data to be written inthe shift registers of the control micro-circuits, and it reduces therate of data entry in the registers and improves driving reliability.

Referring to FIG. 3, there is illustrated a timing diagram of an imageframe division in accordance with a driving method of the presentinvention. A single image frame is divided into n(e.g in FIG. 1 n=6)number of subframes, and a predetermined number of sustaining periodsfor each given subframe is set as S. The number of scan electrodes ofPDP is N and, in general, it has to satisfy a condition S≧N. Slopinglines whose number is identical to the number of the subframes,schematically represents the number of scan electrodes to be selected ina given sustaining period. For example, during a sustaining periodcorresponding to number I, 6 number of the scan electrodes, i.e., A, B,C, D, E and F, are selected. In the following sustaining period, thesenumbers are increased until they reach to N, thereafter each of thesloping lines begins again from first scan electrode, as can be seen byan arrow for one of the sloping lines. In the time of a scan electrodeselection, change in the state of all pixels relating to this electrodeis made in accordance with information to be displayed, that is whetherthe given pixel in the given subframe shall be in “ON” state or “OFF”state.

The selection of a pixel state is performed by generating a scan pulseon a selected scan electrode and a addressing pulse on a selected dataelectrode. Then, the predetermined state of the pixel is maintained bysustaining pulses up to next selection of the same scan electrode.

In accordance with an embodiment of the present invention, a definiteorder of the subframes alternation (interlacing) is set in any twoadjacent subframes of continuous subframes for example, in the first andthe second subframes in the given image frame or the sixth subframe inthe given image frame and the first subframe in the next image frame,the total number of sustaining periods R is set as greater than thepredetermined value selected from an experimental ratio R≧2S/(n+2).

Items of R corresponding to S and n are shown in Table 1.

TABLE 1 s 480 576 n 6 8 10 6 8 10 R 120 96 80 144 115 96

If the number of the sustaining periods is maintained as an odd numberin accordance with the embodiment of the present invention, in case ofS=480 and n=10, a sequence of the numbers of pulses in a subframe is 87,3, 87, 5, 87, 9, 87, 17, 65 and 33 and, according to the above sequence,it is possible to accomplish luminance of 252 gray levels.

Odd scan electrodes and even scan electrodes are separately connected tothe control micro-circuit and total number of sustaining pulses ofadjacent subframes has to be larger than or equal to 82. Therefore, itis possible to make scan pulses by using a control micro-circuit having40 outputs and also to achieve the display efficiency of 100% for asingle image frame as shown in FIG. 3.

In each sustaining period, voltage pulses are provided on electrodes ofthe PDP according to a timing diagram as shown in FIG. 4. In FIG. 4, areference code Us1 represents a voltage value of a sustaining pulseprovided on the first display electrode 6; Us2 depicts a voltage valueof a sustaining pulse supplied on the second display electrode 7; and Uydescribes a voltage value of a scanning pulse applied on the scanelectrode 8. Reference codes UyA, UyB, . . . , UyF represent voltagevalues of scanning pulses generated on selected scan electrodes(i.e.,electrodes located at A, B, . . . , F in FIG. 3) and Ux depicts avoltage value of addressing pulses applied onto the data electrode 9.

At step 1, the positive sustaining pulse 18 is applied on the seconddisplay electrodes 7. At step 2, the positive sustaining pulse 19 issupplied on the first display electrodes 6. Then, at step 3, thepositive sustaining pulse 20 is applied on the second display electrodes7 and, at the same time, a negative scanning pulse 21 which is producedat the scan electrode driver 16 is applied onto all of scan electrodes,e.g., electrodes located at A, B, . . . , F in FIG. 3, selected in agiven period. At step 4, the sustaining pulse 22 is provided on all ofthe scan electrodes. At step 5, a definite level of positive voltage 23is applied onto all of the second display electrodes 7 and at the sametime, a positive voltage 24 having level not exceeding that of thesustaining pulse 22 is provided on the scan electrodes; the scanningpulse 25 are sequentially supplied on the scan electrodes selected atstep 3; and the addressing pulses 26 is supplied on the data electrodes9 in response to information to be displayed.

On the other hand, at the steps 1 to 3, the positive voltage 27 withamplitude identical to that of the addressing pulses 26 is provided onall of the data electrodes 9; At step 4, the positive voltage 28 withlevel not exceeding that of the addressing pulses 26 is applied on allof the data electrodes 9.

By this time, the 4-electrode surface discharge type AC-PDP drivingmethod in accordance with the present invention has been illustrated.The present invention can be applied to a 3-electrode surface dischargetype AC-PDP.

FIGS. 5a and 5 b show a structure of 3-electrodes surface discharge typeAC-PDP, having the same structure as that of the 4-electrode surfacedischarge type AC-PDP shown in FIG. 1 except the second displayelectrodes 7. Therefore, it will be briefly illustrated hereinafter. The3-electrode surface discharge type AC-PDP comprises a plurality ofdisplay lines, each display line having a scan electrode and a displayelectrode, wherein the scan electrodes 8 are connected to the scandriver 16 and the display electrodes 6 are commonly connected to thesustain driver 17. The scan driver 16 provides scanning pulses to thescan electrodes to designate pixels to be displayed in response todisplay information and the sustain driver 17 alternately providessustaining pulses to the commonly connected display electrodes and thescan electrodes so as to display the designated pixels.

According to the present invention, a single image frame is divided intoa plural number e.g., 6 number of subframes, each subframe having aspecific sustaining periods i.e. a specific number of sustaining pulsesin order to display a gray level. Then, after selecting 6 number ofdisplay lines among a plurality of display lines, wherein the number ofthe selected display lines is identical to the number of the dividedsubframes, each subframe is assigned to each of the selected displaylines. As shown in FIGS. 8a and 8 b, by applying a negative writingpulse below a reference voltage onto each selected scan electrodes of aselected display line and a positive writing pulse onto commonlyconnected display electrodes, all pixels of the selected display linesare turned on. In the selective erasing mode illustrated in FIG. 8a, inorder to designate pixels of the selected display lines to be displayedaccording to data pulses provided onto data electrodes, scanning pulsesA to F are sequentially provided on selected scan electrodes Y_(A) toY_(F). On the other hand, in the selective writing mode described inFIG. 8b, after turning off all pixels of the selected display lineswhich are turned on by applying erasing pulses onto all of selected scanelectrodes before scanning, scan pulses A to F are sequentially providedon selected scan electrodes Y_(A) to Y_(F)In the above, the scanningpulses A to F have different phases and exist within one sustainingpulse. At the same time, addressing pulses are supplied onto dataelectrodes X in response to display information. Then, in order todisplay i.e sustain the designated pixels of the selected display lines,specific number of sustaining pulses is alternately applied on displayelectrodes and scan electrodes of the selected display lines. Next,after shifting one line or two lines from before-selected display lines,similarly before-mentioned steps, i.e. selection of display lines,assigning of specific subframe for the selected display lines, turningon of all pixels of the selected display lines, scanning of the selecteddisplay lines, and displaying or sustaining of the designated pixels ofthe selected display lines for each of the assigned subframes carry out.Therefore, if repeating shift above-mentioned and display a specific ofsubframe for selected display lines until each of subframes, i.g. 6number of subframes for all display lines is displayed, display of animage frame is accomplished.

Referring to FIGS. 9a and 9 b, there is described another embodiment ofthe present invention. A width of a negative writing pulse below areference voltage shown in FIGS. 8a and 8 b for turning on the allpixels of the selected display lines can be set as relatively narrowcompared with a interval between adjacent two sustain pulses. Also, in ascanning process, a voltage level provided on all scan electrodes Y cabbe set as lower than that of the sustaining pulse, and at the same time,a positive voltage level is applied onto the commonly connected displayelectrodes. As a result, it is possible to reduce voltage levels of adischarge voltage and an erasing voltage. In addition, it is alsopossible to prevent a discharge erasing error and a writing error.

The present invention can be also applied to 2-electrode type AC-PDPshown in FIGS. 6a and 6 b. While 3-and 4-electrode surface dischargetype AC-PDPs comprises independent display electrodes therein,2-electrode type AC-PDP does not have.

As illustrated above, in embodiment of the present invention, a level ofsustaining pulse has set as 140˜170V, an addressing pulse 80˜100V and asustain period 32 μs. Also, 252 gray levels of display and luminance of260 cd/sq.m have achieved. Furthermore, it is possible to drive an HDTVsystem as well as an NTSC system by increasing the number of subframes.It is possible to multi-scan at different scan points for each of thesubframes and to concurrently display a given subframe and othersubframe. As a result, it is possible to reduce suspending periodsduring processing a single image frame, and there are advantages ofadvanced driving stability, high luminance and improved contrast.

While the present invention has been described with respect to theparticular embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the invention as defined in the followingclaims.

What is claimed is:
 1. A method for driving an AC-type plasma displaypanel capable of displaying gray levels of an image frame which isdivided into n number of subframes, each subframe having predeterminedsustaining periods, wherein, for each sustaining period of the subframe,scanning pulses are provided onto selected scan electrodes, addressingpulses are supplied onto data electrodes in response to displayinformation, and the number of sustaining pulses R included in twoadjacent subframes of continuous subframes is determined as a rate ofR≧2S/(n+2); S represents the total number of sustaining pulses within animage frame and the number of sustaining pulses in a subframe is oddnumber; each pixel including first and second display electrodes whichare disposed in parallel, scan electrodes located close to the first andthe second display electrodes and data electrodes perpendicular to thescan electrodes, a voltage pulse of each of the sustain periods isgenerated by the steps of: (a) providing a positive sustaining pulseonto all of the second display electrodes; (b) supplying the positivesustaining pulse onto all of the first display electrodes; (c) providinga negative writing pulse onto selected scan electrodes, and at the sametime providing the positive sustaining pulse onto all of the seconddisplay electrodes; (d) providing sustaining pulses onto all of the scanelectrodes; (e) determining a voltage level, which is provided onto thesecond display electrodes and the scan electrodes, not greater than anamplitude of the sustaining pulse, subsequently providing negative scanpulses selected in a given sustaining period onto the scan electrodesand applying positive addressing pulses on the data electrodes inresponse to display information, wherein the voltage level in the steps(a) to (c) is determined to be identical to an amplitude of theaddressing pulse and the voltage level in the step (d) is not greaterthan the amplitude of the addressing pulse; and the scan pulse providedonto the selected scan electrodes is a negative pulse and the voltagelevel on the data electrode is not greater than the amplitude of theaddressing pulse.
 2. A method for driving an AC-type plasma displaypanel comprising two substrates separated from each other, displayelectrodes and scan electrodes disposed on one of said two substrates inparallel, a plurality of display lines consisting of one scan electrodeand one or more display electrodes, a dielectric layer covering thedisplay and the scan electrodes, data electrodes disposed on the otherof said two substrates substantially orthogonal to said display lines, anumber of pixels formed on crossing points of a display line and a dataelectrode, spacers formed on one or both of said substrates to partitionsaid pixels, and gas filled in a space between the two substrates, saidmethod comprising the steps of: (a) dividing a single image frame into nnumber of subframes, each of the subframes having predetermined numberof sustaining pulses; (b) selecting display lines whose number isidentical to the number of said divided subframes, assigning specificsubframes to said selected display lines, applying negative writingpulses onto scan electrodes of the selected display lines, at the sametime, providing positive sustaining pulse onto commonly connecteddisplay electrodes, then providing positive sustaining pulses on thescan electrodes of said selected display lines, sequentially providingnegative scanning pulses having different phases on the scan electrodesof said selected display lines and at the same time, applying positiveaddressing pulses on said data electrodes in response to displayinformation in order to designate pixels to be displayed, andalternately supplying the predetermined number of positive sustainingpulses onto said selected scan electrodes and said commonly connecteddisplay electrodes, to thereby display said assigned subframes for eachof said selected display lines; (c) shifting by one or more displayline(s) from each of said selected display lines, and (d) repeating saidshifting of step (c) and displaying of said assigned subframes forselected display lines of step (b) until each of said divided subframesis displayed for all the display lines, to thereby display a imageframe, wherein, at the step (b), widths of the negative writing pulsesprovided onto the selected scan electrodes is narrower than intervalbetween two adjacent sustaining pulses provided onto the scanelectrodes.
 3. The method recited in claim 2, wherein, at the step (b),during providing the negative scan pulses onto the selected scanelectrodes, a voltage level of positive sustaining pulses applied ontothe selected scan electrode is maintained below a voltage level of theother sustaining pulse and at the same time, a fixed level of positivevoltage is provided onto said commonly connected display electrodes. 4.The method as recited in claim 2, wherein at said step (b), beforeproviding negative scanning pulses having different phases on the scanelectrodes of said selected display lines, a constant width of erasingpulses applied onto said selected scan electrodes to erase, i.e. turnoff said pixels.
 5. The method as recited in claim 2, wherein, saiddisplay of assigned subframe for selected display lines continuouscarries out twice.
 6. The method as recited in claim 2, wherein saidscan pulses on the scan electrodes are generated by controlmicro-circuits having “γ” outputs, respectively, each controlmicro-circuit including a shift register, and in a given sustainingperiod, scanning pulse is formed only on one of the outputs of thecontrol micro-circuits.
 7. The method as recited in claim 6, wherein the“γ” value being determined as γ≦R/2, γ represents the number of outputsof the control micro-circuit and R represents the total number of thesustain pulses of the adjacent two subframes.
 8. The method as recitedin claim 6, wherein odd scan electrodes and even scan electrodes areseparately connected to the control micro-circuit.